C8051F39x/37x
10. Temperature Sensor (C8051F390/2/4/6/8 and C8051F370/4 Only)
A fully C8051F33x-compatible temperature sensor is included on the C8051F390/2/4/6/8 and C8051F370/
4 and accessed via the ADC multiplexer in single-ended configuration. For the self-contained precision
temperature sensor, refer to Section 8.
To use the ADC to measure the temperature sensor, the ADC mux channel should be configured to con-
nect to the temperature sensor. The temperature sensor transfer function is shown in Figure 10.1. The out-
put voltage (V
) is the positive ADC input when the ADC multiplexer is set correctly. The TEMPE bit in
TEMP
register REF0CN enables/disables the temperature sensor, as described in SFR Definition 12.1. While dis-
abled, the temperature sensor defaults to a high impedance state and any ADC measurements performed
on the sensor will result in meaningless data. Refer to Table 7.11 for the slope and offset parameters of the
temperature sensor.
VTEMP = (Slope x TempC) + Offset
TempC = (VTEMP - Offset) / Slope
Slope (V / deg C)
Offset (V at 0 Celsius)
Temperature
Figure 10.1. Temperature Sensor Transfer Function
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Preliminary Rev. 0.71
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